Amazy Dayzees, but only in the Pit of 100 Trials, because they do massive damage, they won't run away, and can easily send you to sleep.
...they murdered me when I was near the end... Also with those Purple Bulky Bob-ombs as well, but mostly was the Amazy Dayzee's fault.
Wizzerds weren't much of a problem when I played, honestly, even though they were tough, they never game me the problems an Amazy Dayzee gave.